Pistachio culture

Pistachio locationPistachios should be planted in full sun. The size of the slow growing trees can be further controlled by pruning. When planting, avoid rough handling since the budded tops are easily broken away from the under stock.

SoilThe trees do best on soils that are deep, friable and well drained but moisture retaining. It can, however, survive in poor, stony, calcareous, highly alkaline or slightly acid, or even saline soils. The root is deeply penetrating.

IrrigationPistachios will tolerate considerable drought but do best with deep, infrequent watering.

FertilizationSince pistachios grow slowly, they do not require large quantities of nitrogen fertilizer. A spring feeding of a complete fertilizer such as 10-10-10 NPK should be adequate.

PruningPruning can be important to commercial growers in order to shape the trees for mechanical harvesting, but less so for the home orchards. The trees should be trained to a modified central leader with 4 or 5 main scaffold limbs branching about 4 ft. from the ground. After initial training, Little pruning is needed except to remove interfering branches. Heavy pruning reduces yield.

PropagationThe pistachio is usually propagated in California by budding or grafting selected scions onto seedling stocks of P. atlantics, P. terebinthus and P. integerrima. These rootstock species are used because of their vigor and resistance to nematodes and soil borne fungi.

Pests and diseasesA number of fungi attack the pistachio. The most serious fungal disease in California is vertically wilt, which can quickly kill trees of varying age.Most pistachios are now grafted to vertically resistant P. integerrima rootstock. The trees are also sensitive to the oak root fungus, Armillary melee. Insect pests include the aphid, Ana pleura lentissimo and several species of leaf-footed bugs and stink bugs. The nuts are also very attractive to squirrels and some birds, including blue jays and woodpeckers.

HarvestThe nuts are harvested when the husk or hull covering the shell becomes fairly loose. A single shaking will bring down the bulk of the matured nuts, which can be caught on a tarp or canvas. A fully mature tree may produce as much as 50 pounds of dry, hulled nuts. The hulls should be removed soon after to prevent staining of the shells. To enhance splitting, the hulled nuts may then be dipped into water to moisten the shell and spread out in the sun to dry. One method of salting the split nuts is to boil them in a salt solution for a few minutes, then retry and store them. Stored in plastic bags pistachios will last for at least 4 to 6 weeks in the refrigerator. Frozen they will last for months. The pistachio is unique in the nut trade due to its semi-split shell which enables the processor to roast and salt the kernel without removing the shell, and which at the same time serves as a convenient form of packaging.About 90% of California pistachios are consumed as in-shell snacks. Shelled pistachios are utilized commercially in confectionery, ice cream, candies, sausages, bakery goods and flavoring for puddings. They can also be added to dressings, casseroles and other dishes.

Commercial potentialPistachio nuts are considered one of the prime edible nuts, along with almonds, macadamias and cashews.The production of pistachio nuts in California has increased dramatically in recent years, from some 4-1/2 million pounds in 1977 to over 80 million today. With additional promotion, production is estimated to ultimately exceed 129 million pounds.

Countries of originThis Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.